A lysosomal or secreted, thiol-dependent peptidase, most active at
acidic pH.

Commonly studied with folylpoly-gamma-glutamate as substrate, with
which the initial cleavage may release glutamate or poly-gamma-
glutamate of two or more residues, according to the species of origin
of the enzyme.

Final products are pteroyl-alpha-glutamate (folic acid) and free
glutamate.

Highly specific for the gamma-glutamyl bond, but not for the
C-terminal amino acid (leaving group).

Action on gamma-glutamyl bonds is independent of an N-terminal
pteroyl moiety, but it is not known whether an N-terminal gamma-Glu
residue can be hydrolyzed.